In the case of rail vehicles, the transmission of braking forces and acceleration forces occurs at the wheel/rail contact point. It is here that the transmission takes place by frictional engagement by means of brake frictional forces acting between components which are composed of steel. The frictional conditions of this frictional engagement are dependent, inter alia, on the temperature, the degree of soiling and the speed. In this context it is possible for the braking force to be given a larger setting during braking than the maximum braking frictional force which can be transmitted at the contact point, which causes the wheels of one or more axles to lock. In such cases, the sliding friction which then occurs causes undesired formation of flat points and a reduction in the transmittable braking frictional forces because the coefficient of friction drops starting from a maximum at a very low relative speed as the relative speed between the frictional parties becomes larger. To prevent this, what are referred to as antislip systems or antislip regulation systems are used which, in the case of locking of a brake, reduce the braking force at the axle in question to arrive again approximately in the region of the static friction or the region of an optimum braking slip.
This reduction in the braking force, performed by the antislip regulation, at axles with locking brakes, leads to a situation in which the desired deceleration of the rail vehicle or rail vehicle train is not achieved and the braking distance is lengthened. This is to be avoided.
German Patent Application No. 10 2008 063 892 A1 discloses a method in which fluctuations in the frictional conditions between the wheel or wheel set and rail are compensated starting from a certain limiting value by adapting the braking force and/or the braking torque. In particular if, when there are a plurality of brake actuators, an unpermitted deviation of a variable representing the frictional conditions between the wheel and the rail is detected at one brake actuator, the braking force at the one brake actuator is increased and for the purpose of compensation the braking force which is generated by a further braking actuator, at which a permitted deviation or no deviation of the variable representing the frictional conditions between the wheel and the rail is present, is reduced.